Field
Embodiments of the present invention generally relate to apparatus for heating substrates.
Description of the Related Art
Semiconductor substrates are processed for a wide variety of applications, including the fabrication of integrated devices and microdevices. One method of processing substrates includes depositing a material, such as a dielectric material or a conductive metal, on an upper surface of the substrate. For example, epitaxy is a deposition process that grows a thin, ultra-pure layer, usually of silicon or germanium on a surface of a substrate. The material may be deposited in a lateral flow chamber by flowing a process gas parallel to the surface of a substrate positioned on a support, and thermally decomposing the process gas to deposit a material from the gas onto the substrate surface.
The most common epitaxial (epi) film deposition reactors used in modern silicon technology are similar in design. Besides substrate and process conditions, however, the reactor design is essential for film quality in epitaxial growth which uses a combination of precision gas flow and accurate temperature control. Flow control, chamber volume, and chamber heating rely on the design of the upper and lower domes which influence epitaxial deposition uniformity. The prior upper dome design restricts process uniformity with sudden large changes in cross sectional area above the substrate which negatively influences flow uniformity, induces turbulence, and affect overall uniformity of deposition gas concentration over the substrate. Similarly, the prior lower dome design restricts process uniformity with sudden large changes in cross sectional area under the substrate which negatively influences temperature uniformity and moves the lamp head far away from the substrate, resulting in poor overall thermal uniformity and minimal zonal control. This in turn limits process uniformity and overall chamber process tenability.
Since flow characteristics directly impact the film performance on the substrate, there is a need for a deposition apparatus which provides a uniform thermal field across the substrate with strong center-to-edge tuning capabilities and a balanced flow field throughout the process chamber.